drivers/usb/mtu3/mtu3_dr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * mtu3_dr.c - dual role switch and host glue layer
   4  *
   5  * Copyright (C) 2016 MediaTek Inc.
   6  *
   7  * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
   8  */
   9
  10 #include <linux/debugfs.h>
  11 #include <linux/irq.h>
  12 #include <linux/kernel.h>
  13 #include <linux/of_device.h>
  14 #include <linux/pinctrl/consumer.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/uaccess.h>
  17
  18 #include "mtu3.h"
  19 #include "mtu3_dr.h"
  20
  21 #define USB2_PORT 2
  22 #define USB3_PORT 3
  23
  24 enum mtu3_vbus_id_state {
  25         MTU3_ID_FLOAT = 1,
  26         MTU3_ID_GROUND,
  27         MTU3_VBUS_OFF,
  28         MTU3_VBUS_VALID,
  29 };
  30
  31 static void toggle_opstate(struct ssusb_mtk *ssusb)
  32 {
  33         if (!ssusb->otg_switch.is_u3_drd) {
  34                 mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
  35                 mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
  36         }
  37 }
  38
  39 /* only port0 supports dual-role mode */
  40 static int ssusb_port0_switch(struct ssusb_mtk *ssusb,
  41         int version, bool tohost)
  42 {
  43         void __iomem *ibase = ssusb->ippc_base;
  44         u32 value;
  45
  46         dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__,
  47                 version, tohost ? "host" : "device");
  48
  49         if (version == USB2_PORT) {
  50                 /* 1. power off and disable u2 port0 */
  51                 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
  52                 value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS;
  53                 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
  54
  55                 /* 2. power on, enable u2 port0 and select its mode */
  56                 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
  57                 value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS);
  58                 value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) :
  59                         (value & (~SSUSB_U2_PORT_HOST_SEL));
  60                 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
  61         } else {
  62                 /* 1. power off and disable u3 port0 */
  63                 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
  64                 value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS;
  65                 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
  66
  67                 /* 2. power on, enable u3 port0 and select its mode */
  68                 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
  69                 value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS);
  70                 value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) :
  71                         (value & (~SSUSB_U3_PORT_HOST_SEL));
  72                 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
  73         }
  74
  75         return 0;
  76 }
  77
  78 static void switch_port_to_host(struct ssusb_mtk *ssusb)
  79 {
  80         u32 check_clk = 0;
  81
  82         dev_dbg(ssusb->dev, "%s\n", __func__);
  83
  84         ssusb_port0_switch(ssusb, USB2_PORT, true);
  85
  86         if (ssusb->otg_switch.is_u3_drd) {
  87                 ssusb_port0_switch(ssusb, USB3_PORT, true);
  88                 check_clk = SSUSB_U3_MAC_RST_B_STS;
  89         }
  90
  91         ssusb_check_clocks(ssusb, check_clk);
  92
  93         /* after all clocks are stable */
  94         toggle_opstate(ssusb);
  95 }
  96
  97 static void switch_port_to_device(struct ssusb_mtk *ssusb)
  98 {
  99         u32 check_clk = 0;
 100
 101         dev_dbg(ssusb->dev, "%s\n", __func__);
 102
 103         ssusb_port0_switch(ssusb, USB2_PORT, false);
 104
 105         if (ssusb->otg_switch.is_u3_drd) {
 106                 ssusb_port0_switch(ssusb, USB3_PORT, false);
 107                 check_clk = SSUSB_U3_MAC_RST_B_STS;
 108         }
 109
 110         ssusb_check_clocks(ssusb, check_clk);
 111 }
 112
 113 int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on)
 114 {
 115         struct ssusb_mtk *ssusb =
 116                 container_of(otg_sx, struct ssusb_mtk, otg_switch);
 117         struct regulator *vbus = otg_sx->vbus;
 118         int ret;
 119
 120         /* vbus is optional */
 121         if (!vbus)
 122                 return 0;
 123
 124         dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off");
 125
 126         if (is_on) {
 127                 ret = regulator_enable(vbus);
 128                 if (ret) {
 129                         dev_err(ssusb->dev, "vbus regulator enable failed\n");
 130                         return ret;
 131                 }
 132         } else {
 133                 regulator_disable(vbus);
 134         }
 135
 136         return 0;
 137 }
 138
 139 /*
 140  * switch to host: -> MTU3_VBUS_OFF --> MTU3_ID_GROUND
 141  * switch to device: -> MTU3_ID_FLOAT --> MTU3_VBUS_VALID
 142  */
 143 static void ssusb_set_mailbox(struct otg_switch_mtk *otg_sx,
 144         enum mtu3_vbus_id_state status)
 145 {
 146         struct ssusb_mtk *ssusb =
 147                 container_of(otg_sx, struct ssusb_mtk, otg_switch);
 148         struct mtu3 *mtu = ssusb->u3d;
 149
 150         dev_dbg(ssusb->dev, "mailbox state(%d)\n", status);
 151
 152         switch (status) {
 153         case MTU3_ID_GROUND:
 154                 switch_port_to_host(ssusb);
 155                 ssusb_set_vbus(otg_sx, 1);
 156                 ssusb->is_host = true;
 157                 break;
 158         case MTU3_ID_FLOAT:
 159                 ssusb->is_host = false;
 160                 ssusb_set_vbus(otg_sx, 0);
 161                 switch_port_to_device(ssusb);
 162                 break;
 163         case MTU3_VBUS_OFF:
 164                 mtu3_stop(mtu);
 165                 pm_relax(ssusb->dev);
 166                 break;
 167         case MTU3_VBUS_VALID:
 168                 /* avoid suspend when works as device */
 169                 pm_stay_awake(ssusb->dev);
 170                 mtu3_start(mtu);
 171                 break;
 172         default:
 173                 dev_err(ssusb->dev, "invalid state\n");
 174         }
 175 }
 176
 177 static void ssusb_id_work(struct work_struct *work)
 178 {
 179         struct otg_switch_mtk *otg_sx =
 180                 container_of(work, struct otg_switch_mtk, id_work);
 181
 182         if (otg_sx->id_event)
 183                 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
 184         else
 185                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 186 }
 187
 188 static void ssusb_vbus_work(struct work_struct *work)
 189 {
 190         struct otg_switch_mtk *otg_sx =
 191                 container_of(work, struct otg_switch_mtk, vbus_work);
 192
 193         if (otg_sx->vbus_event)
 194                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 195         else
 196                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
 197 }
 198
 199 /*
 200  * @ssusb_id_notifier is called in atomic context, but @ssusb_set_mailbox
 201  * may sleep, so use work queue here
 202  */
 203 static int ssusb_id_notifier(struct notifier_block *nb,
 204         unsigned long event, void *ptr)
 205 {
 206         struct otg_switch_mtk *otg_sx =
 207                 container_of(nb, struct otg_switch_mtk, id_nb);
 208
 209         otg_sx->id_event = event;
 210         schedule_work(&otg_sx->id_work);
 211
 212         return NOTIFY_DONE;
 213 }
 214
 215 static int ssusb_vbus_notifier(struct notifier_block *nb,
 216         unsigned long event, void *ptr)
 217 {
 218         struct otg_switch_mtk *otg_sx =
 219                 container_of(nb, struct otg_switch_mtk, vbus_nb);
 220
 221         otg_sx->vbus_event = event;
 222         schedule_work(&otg_sx->vbus_work);
 223
 224         return NOTIFY_DONE;
 225 }
 226
 227 static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
 228 {
 229         struct ssusb_mtk *ssusb =
 230                 container_of(otg_sx, struct ssusb_mtk, otg_switch);
 231         struct extcon_dev *edev = otg_sx->edev;
 232         int ret;
 233
 234         /* extcon is optional */
 235         if (!edev)
 236                 return 0;
 237
 238         otg_sx->vbus_nb.notifier_call = ssusb_vbus_notifier;
 239         ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB,
 240                                         &otg_sx->vbus_nb);
 241         if (ret < 0)
 242                 dev_err(ssusb->dev, "failed to register notifier for USB\n");
 243
 244         otg_sx->id_nb.notifier_call = ssusb_id_notifier;
 245         ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
 246                                         &otg_sx->id_nb);
 247         if (ret < 0)
 248                 dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
 249
 250         dev_dbg(ssusb->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n",
 251                 extcon_get_state(edev, EXTCON_USB),
 252                 extcon_get_state(edev, EXTCON_USB_HOST));
 253
 254         /* default as host, switch to device mode if needed */
 255         if (extcon_get_state(edev, EXTCON_USB_HOST) == false)
 256                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 257         if (extcon_get_state(edev, EXTCON_USB) == true)
 258                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 259
 260         return 0;
 261 }
 262
 263 /*
 264  * We provide an interface via debugfs to switch between host and device modes
 265  * depending on user input.
 266  * This is useful in special cases, such as uses TYPE-A receptacle but also
 267  * wants to support dual-role mode.
 268  */
 269 static void ssusb_mode_manual_switch(struct ssusb_mtk *ssusb, int to_host)
 270 {
 271         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 272
 273         if (to_host) {
 274                 ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_HOST);
 275                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
 276                 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
 277         } else {
 278                 ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_DEVICE);
 279                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 280                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 281         }
 282 }
 283
 284 static int ssusb_mode_show(struct seq_file *sf, void *unused)
 285 {
 286         struct ssusb_mtk *ssusb = sf->private;
 287
 288         seq_printf(sf, "current mode: %s(%s drd)\n(echo device/host)\n",
 289                 ssusb->is_host ? "host" : "device",
 290                 ssusb->otg_switch.manual_drd_enabled ? "manual" : "auto");
 291
 292         return 0;
 293 }
 294
 295 static int ssusb_mode_open(struct inode *inode, struct file *file)
 296 {
 297         return single_open(file, ssusb_mode_show, inode->i_private);
 298 }
 299
 300 static ssize_t ssusb_mode_write(struct file *file,
 301         const char __user *ubuf, size_t count, loff_t *ppos)
 302 {
 303         struct seq_file *sf = file->private_data;
 304         struct ssusb_mtk *ssusb = sf->private;
 305         char buf[16];
 306
 307         if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
 308                 return -EFAULT;
 309
 310         if (!strncmp(buf, "host", 4) && !ssusb->is_host) {
 311                 ssusb_mode_manual_switch(ssusb, 1);
 312         } else if (!strncmp(buf, "device", 6) && ssusb->is_host) {
 313                 ssusb_mode_manual_switch(ssusb, 0);
 314         } else {
 315                 dev_err(ssusb->dev, "wrong or duplicated setting\n");
 316                 return -EINVAL;
 317         }
 318
 319         return count;
 320 }
 321
 322 static const struct file_operations ssusb_mode_fops = {
 323         .open = ssusb_mode_open,
 324         .write = ssusb_mode_write,
 325         .read = seq_read,
 326         .llseek = seq_lseek,
 327         .release = single_release,
 328 };
 329
 330 static int ssusb_vbus_show(struct seq_file *sf, void *unused)
 331 {
 332         struct ssusb_mtk *ssusb = sf->private;
 333         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 334
 335         seq_printf(sf, "vbus state: %s\n(echo on/off)\n",
 336                 regulator_is_enabled(otg_sx->vbus) ? "on" : "off");
 337
 338         return 0;
 339 }
 340
 341 static int ssusb_vbus_open(struct inode *inode, struct file *file)
 342 {
 343         return single_open(file, ssusb_vbus_show, inode->i_private);
 344 }
 345
 346 static ssize_t ssusb_vbus_write(struct file *file,
 347         const char __user *ubuf, size_t count, loff_t *ppos)
 348 {
 349         struct seq_file *sf = file->private_data;
 350         struct ssusb_mtk *ssusb = sf->private;
 351         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 352         char buf[16];
 353         bool enable;
 354
 355         if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
 356                 return -EFAULT;
 357
 358         if (kstrtobool(buf, &enable)) {
 359                 dev_err(ssusb->dev, "wrong setting\n");
 360                 return -EINVAL;
 361         }
 362
 363         ssusb_set_vbus(otg_sx, enable);
 364
 365         return count;
 366 }
 367
 368 static const struct file_operations ssusb_vbus_fops = {
 369         .open = ssusb_vbus_open,
 370         .write = ssusb_vbus_write,
 371         .read = seq_read,
 372         .llseek = seq_lseek,
 373         .release = single_release,
 374 };
 375
 376 static void ssusb_debugfs_init(struct ssusb_mtk *ssusb)
 377 {
 378         struct dentry *root;
 379
 380         root = debugfs_create_dir(dev_name(ssusb->dev), usb_debug_root);
 381         ssusb->dbgfs_root = root;
 382
 383         debugfs_create_file("mode", 0644, root, ssusb, &ssusb_mode_fops);
 384         debugfs_create_file("vbus", 0644, root, ssusb, &ssusb_vbus_fops);
 385 }
 386
 387 static void ssusb_debugfs_exit(struct ssusb_mtk *ssusb)
 388 {
 389         debugfs_remove_recursive(ssusb->dbgfs_root);
 390 }
 391
 392 void ssusb_set_force_mode(struct ssusb_mtk *ssusb,
 393                           enum mtu3_dr_force_mode mode)
 394 {
 395         u32 value;
 396
 397         value = mtu3_readl(ssusb->ippc_base, SSUSB_U2_CTRL(0));
 398         switch (mode) {
 399         case MTU3_DR_FORCE_DEVICE:
 400                 value |= SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG;
 401                 break;
 402         case MTU3_DR_FORCE_HOST:
 403                 value |= SSUSB_U2_PORT_FORCE_IDDIG;
 404                 value &= ~SSUSB_U2_PORT_RG_IDDIG;
 405                 break;
 406         case MTU3_DR_FORCE_NONE:
 407                 value &= ~(SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG);
 408                 break;
 409         default:
 410                 return;
 411         }
 412         mtu3_writel(ssusb->ippc_base, SSUSB_U2_CTRL(0), value);
 413 }
 414
 415 int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
 416 {
 417         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 418
 419         INIT_WORK(&otg_sx->id_work, ssusb_id_work);
 420         INIT_WORK(&otg_sx->vbus_work, ssusb_vbus_work);
 421
 422         if (otg_sx->manual_drd_enabled)
 423                 ssusb_debugfs_init(ssusb);
 424         else
 425                 ssusb_extcon_register(otg_sx);
 426
 427         return 0;
 428 }
 429
 430 void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
 431 {
 432         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 433
 434         if (otg_sx->manual_drd_enabled)
 435                 ssusb_debugfs_exit(ssusb);
 436
 437         cancel_work_sync(&otg_sx->id_work);
 438         cancel_work_sync(&otg_sx->vbus_work);
 439 }